SOLUTION: In a group of children, each child gives one gift to the other.If total gifts are 90, then find the number children in the group.

Algebra ->  Coordinate Systems and Linear Equations  -> Linear Equations and Systems Word Problems -> SOLUTION: In a group of children, each child gives one gift to the other.If total gifts are 90, then find the number children in the group.      Log On


   

Question 846972: In a group of children, each child gives one gift to the other.If total gifts are 90, then find the number children in the group.
Answer by ewatrrr(24785) About Me  (Show Source):
You can put this solution on YOUR website!
 

Hi,

each child gives one gift to the other 

total gifts are 90

n%28n-1%29+=+90

  n(n-1) = 90

 n^2 - n = 90

 n^2 - n - 90 = 0     (Tossing out the negative solution for unit measure)

(n-10)(n+9) = 0 ,   n = 10 children in the group